Organic Fertilizer for the Lawn

Weighing the options of organic, chemical and slow-release fertilizers

Most homeowners want at least a decent lawn, but don’t want to pollute their well or foul up the environment in the process. Those concerns are largely behind an increased interest lately in organic lawn care — a system that relies on fertilizer from natural nutrient sources such as dehydrated manure, dried blood, bone meal and kelp instead of synthetic fertilizers from a manufacturing plant. Organic fertilizer offers several advantages over the more popular synthetic fertilizers, better known as “chemical” fertilizers. However, like most things in life, there are some cons of organic fertilizers that go along with the pros.

The newest fertilizer option: Slow-release nitrogen fertilizers

A third and newer fertilizer option is lawn fertilizer products that contain slow-release nitrogen (a.k.a. time-release nitrogen); a technology that provides many of the advantages of organic fertilizers. These slow-release nitrogen fertilizer products are similar to timed-release medications in that the dose is released gradually as the various coatings break down. Several types of slow-release nitrogen are used in the fertilizer, and differing amounts can be mixed with standard nitrogen sources to regulate how much is released and at what rate.

Slow-release fertilizers can spread out the nitrogen release over 12 weeks or more, which eliminates unwanted surges in grass growths, cuts down applications to twice a year and lessens runoff because less material is applied.

Even newer to the market are fertilizers that are both high in slow-release nitrogen and phosphate free. These are aimed at homeowners who want benefits similar to organic fertilizer and who have lawns that already have plenty of phosphorus.

Choices, choices, choices! Even so, in the long run, a little homework can save money, produce a better lawn and be kinder to the environment all at the same time.

Organic fertilizer: A lower-and-slower approach to fertilization

The organic fertilizer approach's main advantage is that natural materials must break down in order for the nutrients to be released in a form that the grass roots can use. This takes place gradually, meaning the feeding process is slower and longer lasting than with immediately available water-soluble chemicals in some fertilizers.

What’s especially beneficial is that organic lawn fertilizer materials break down at rates that correlate with the times when lawns need them most. When the soil warms in spring and rain increases, organic fertilizer breaks down faster. That’s also when grass growth increases and fertilizer needs go up. But when the rains shut off in summer and soil microbe activity slows in heat and drought, grass growth slows and nutrition demands go down. Those same conditions in turn slow the breakdown of organic fertilizers.

By contrast, grass roots quickly take up chemical fertilizer — especially nitrogen — and use it to produce the dense, dark-green stand of turfgrass that most people want. If the fertilizer contains only water soluble nitrogen, whatever the roots don’t use either leaches out of the root zone or is carried away by runoff so that most of it is gone in six to eight weeks. That’s why most chemical lawn-care programs, including the ones you buy at the home centers or sign up for with the lawn service, require four to five fertilizer applications per growing season.

Note: Greenview Fairway Formula Fertilizers contain a unique, patented slow release nitrogen technology that extends the release of nutrients to the grass plant for even feeding and lasts up to 16 weeks, outperforming other brands of chemical fertilizers that contain only water soluble nitrogen.

Pro-organic lawn-growers point to three other benefits of the lower-and-slower approach of organic fertilizer:

Organic fertilizer doesn’t cause growth spurts after feedings that lead to excess mowing.

Organic fertilizer is less likely to encourage thatch problems in the lawn than chemical fertilizer.

The dangers of over-applying fertilizer to your lawn

On the other hand, any fertilizer, chemical or organic, can be harmful to the environment if it’s applied to excess or applied at the wrong time or in the wrong way. Example: If you use a broadcast spreader and accidentally scatter the fertilizer grains on the driveway or sidewalk, most of those nutrients are going to end up in the storm sewers and waterways, whether it’s synthetic or primarily dried chicken manure. Or if you apply your fertilizer right before a torrential rain, again, much of the fertilizer can run off — especially if your lawn is thin or growing in compacted clay soil.

A bigger issue is routinely applying fertilizer whether the lawn needs it or not. In an ideal situation, only the nutrients that the lawn needs would be applied and only in the amounts it needs in order to reduce the excess hanging around to run off. The only way to determine that is to test the soil’s nutrient levels and pH (a measure of soil acidity) before starting any lawn program. Most land-grant university Extension programs offer do-it-yourself testing kits, and many private soil-testing companies offer the services. Tests don’t have to be done every year, but they’re a good idea at the beginning of any program and then every three to four years.

These tests produce reports on the various soil nutrient levels and give recommendations on exactly what breakdown of fertilizer is needed and what levels are needed. This is why so many different kinds of fertilizer options are on the market — to help homeowners tailor a product to their particular lawn’s needs.

Fertilizer performance differences

A more commonly noticed disadvantage to organic lawn fertilizer is that it doesn’t produce as thick and green of a lawn as does synthetic fertilizer. That’s part of the tradeoff for the advantages of the low-slow mechanics of organic fertilizer. The difference is a lot like the difference between someone who lifts weights at a health club and a bodybuilder. Bodybuilders push themselves to the limit, stack on as much weight as they can handle and take supplements to maximize muscle-building nutrition. The health-club-goer lifts more moderate weights and ends up reasonably strong and fit but not muscular enough to win any Mr. America competitions. Bottom line: Neither is inherently right or wrong… it’s a matter of goals. If you are looking to have a beautiful, lush, dark green lawn, a chemical fertilizer with a high percentage of slow release nitrogen technology is an environmentally friendly solution.

Two other potential drawbacks for organic fertilizer are that some have a manure smell (it usually dissipates in a few days) and it’s usually more expensive per bag than synthetic fertilizer.